This is a phase II open label clinical trial of SU101, an inhibitor of platelet-derived growth factor signaling, for recurrent anaplastic astrocytoma (grade III astrocytoma) of the brain. The study is sponsored by the Sugen Corporation. SU101 has shown activity in Phase I and I/II trials against glioblastoma multiforme (grade IV astrocytoma), and the maximum tolerated dose and major toxicities have been determined. The primary endpoint is time to progression. Sugen plans to enroll 60 patients nationally. We project enrollment of 12 patients over 2 years at UMMC. Patients will receive 6hour infusions in the GCRC outpatient setting on 10 occasions during the first 8 week cycle and 7 occasions during subsequent cycles. These patients will also need blood drawn in the GCRC 4 times during each cycle and sent to a reference lab.